Same-sex marriage arguments may not sway vote, survey finds

Weeks of debate on same-sex marriage may not have shifted Australians' votes on the issue, according to a poll that has found 60 per cent support for change.

The survey taken by YouGov on the eve of the plebiscite result found that hearing the key arguments for and against allowing same-sex marriage "appear to have very little impact on whether respondents support it" according to an analysis by the US Studies Centre at the University of Sydney, which commissioned the survey.

The centre's poll, which also canvassed views in the United States, found that Americans are more likely than Australians to support the right of business owners to refuse services for same-sex weddings because they have religious objections. But the difference was not huge, with 50 per cent of Americans and 43 per cent of Australians saying business owners should have the right to refuse.

Supporters during a marriage equality rally in Melbourne. Photo: David Crosling

Those disagreeing or not having a position were 35 per cent and 15 per cent in the US, and 39 per cent and 17 per cent in Australia.

The Australian Bureau of Statistics is set to release the results of the Australian plebiscite next Wednesday at 10am.

Overall, 60 per cent of Australian respondents supported the right of same-sex couples to marry, 32 per cent were opposed and 8 per cent were undecided. That compared with 48 per cent support, 40 per cent opposition and 12 per cent irresolution in the US.

To gauge the effect of the main arguments for and against same-sex marriage, the pollsters asked some people simply whether they approved of same-sex marriage but asked others a question that embedded the key "yes" and "no" arguments.

The "yes" argument was that it promoted equality. The "no" argument was that it was a threat to religious freedom, for example bakers being forced to make wedding cakes for same-sex couples or schools being required to teach about same-sex relationships.

Including those arguments made no significant difference to the results, the centre's analysis found, indicating that "both arguments carry equal force, cancelling each other out", and that therefore "these common arguments for and against [same-sex marriage] appear to have very little impact on respondents' expressed support for same-sex marriage".